A journalist imprisoned for treason after disclosing how Russia dumped nuclear waste in the Pacific Ocean has been released on parole.

Grigory Pasko, a former naval officer, was sentenced to four years in jail in December 2001.

Grigory Pasko will be able to return home in the next couple of days Maria Stebnovskaya, judge

After his release for good behaviour, Pasko said his campaign was not over.

"We are going to work to achieve the full exoneration of my good name," he said outside the prison.

"We're going to do everything to ensure that this criminal case is recognised as a falsification, that is, the way it is in fact."

In June 2002, the Russian Supreme Court rejected an appeal against Pasko's conviction.

Pasko's lawyer, Ivan Pavlov, said his client would serve the remaining 16 months of his sentence at home, under police surveillance, the French news agency AFP reported.

Announcing the ruling, Ussuryisk court judge Maria Stebnovskaya said: "Grigory Pasko will be able to return home in the next couple of days.

"This is how long it will take to file all necessary documents."

Under Russian law, a prisoner who has served two-thirds of his sentence and behaved well can apply for release.

"The court made its decision [to release Pasko] mainly because our client had never once violated the jail's rules and regulations," Mr Pavlov told reporters after the hearing.

Whistle-blower

Pasko was arrested by the Russian security service in 1997, while working as a journalist for the Russian Pacific Fleet's newspaper.

Pasko was convicted of treason at a second trial

He was investigated after writing a story about how the fleet dumped nuclear waste at sea.

At his first trial in July 1999, Pasko was convicted only of abuse of office and given a three-year sentence.

He was immediately set free under a prisoner amnesty.

Pasko appealed to the military section of Russia's Supreme Court to clear his name entirely, but the court said he should be retried on the espionage and treason charges.

In a later trial, Pasko was convicted of treason for handing over to Japan's NHK state television a secret document giving details of a military base that held radioactive waste.

Pasko said he was being punished for reporting on environmental abuses by the navy.